1. Field of the Invention
This invention relates to resolution enhancement, and more specifically, to a system of beam narrowing for resolution enhancement utilizing a Fabry-Perot cavity and a method therefor.
2. Description of the Related Art
The ability to resolve surfaces of interest and any details thereon is generally limited by the diffraction limits of the optics utilized. The physical specifications of the optical system and the illumination system determine the value of this lower limit of resolution. The effects of the diffraction limits are a result of the propagation of the electromagnetic field.
Some of the known methods related to the minimization of the diffraction limitations, or compensating for them, include immersion microscopy, near-field imaging, confocal imaging, phase modulation of microlithographic masks, etc. These known methods all have drawbacks however. The drawbacks may result from the need for special system configurations, or due to the specifics of each of the known methods, their practicality is limited to special case applications, and the known methods are also quite expensive and task dedicated. Thusxe2x80x94the problem still to be solved is resolution enhancement in a system and method that is easily and inexpensively implemented for a large number of applications. A problem requiring a solution that addresses the resolution/diffraction limitations is a system of beam narrowing for resolution enhancement utilizing a Fabry-Perot cavity.
Therefore, a need existed for a system for resolution enhancement and a method therefor. Another need existed for a system for resolution enhancement that is inexpensive to implement and a method therefor.
It is an object of the present invention to provide a system for resolution enhancement and a method therefor. It is another object of the present invention to provide for a system for resolution enhancement that is inexpensive to implement and a method therefor.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.
According to one aspect of the invention, a first embodiment of a system of beam narrowing for resolution enhancement is disclosed. The system of beam narrowing for resolution enhancement includes an illumination system, a surface of interest positioned in a plane relative to the illumination system, and an optical focusing system positioned in a plane relative to the illumination system. The optical focusing system cooperates with the illumination system to image a light source through the illumination system and through the optical focusing system onto a selected target surface. A reference plate is included and is positioned between the optical focusing system and the surface of interest. The reference plate has an inner partly reflective surface substantially parallel to the surface of interest, and the reflective surface is further positioned at a tuned optical distance from the surface of interest and the tuned optical distance is defined as that value where the image spot size of the light source on the selected target surface is minimized.
According to another aspect of the invention, a second embodiment of a system of beam narrowing for resolution enhancement is disclosed. The second embodiment of the system of beam narrowing for resolution enhancement includes an illumination system, a surface of interest positioned in a plane relative to the illumination system and an optical focusing system positioned in a plane relative to the illumination system. The optical focusing system cooperates with the illumination system to image a light source through the illumination system and through the optical focusing system onto a selected target surface. A reference plate is included and is positioned between the optical focusing system and the surface of interest. The reference plate has an inner partly reflective surface substantially parallel to the surface of interest. Several other partly reflective surfaces are included and are positioned between the first partly reflective surface and the surface of interest and are positioned substantially parallel to the first partially reflective surface. The relative distances between any and all of the partly reflective surfaces and the selected target surface are tuned so that the image spot size of the light source on the selected target surface is at a minimum.